Machine-table-reversing mechanism



May 29, 1923. 1,456,968

G. BROWN ET AL MACHINE TABLE REVERSING MECHANISM Filed June 29 1921 2 Sheets-Sheet l Gre om Brown v Albgrf Turner W mean. {WW

May 29, 1923. 1,456,968

G. BROWN ET AL MACHINE TABLE REVERSING MECHANISM Filed June 29 1921 2 Sheets-Sheet 2 3 2 7/ I NH,

MN a l llllllllllll lllllllllllll W max; I Gregogg Brown MW. 4% AlberT urner Patented May 29, 1923.

GREGORY BROWN AND ALBERT TURNER, OF WORCESTER, MASSACHUSETTS,

ASSIGNORS TO NORTON COMPANY, OF WORCESTER, MASSACHUSETTS, A COR- PORATION OF MASSACHUSETTS.

IYIACHINE-TABLE-REVERSING MECHANISM.

Application filed June 29, 1921. Serial No. 481,178;

To all whom it may concern:

Be it known that we, GREGORY BROWN and ALBERT TURNER, citizens of the United States of America, residing at Vs orcester, in the county of WVorcesterand State of Massachusetts, have invented certain new and useful Improvements in Machine-Table-Reversing Mechanisms, of which the following is a full, clear, and exact specification.

This invention relates to driving and reversing mechanisms and is particularly intended for gradually starting and stopping the reciprocable table of a machine tool without serious shocks and driving it atfla normal rate between reversals.

It is oneobject of our invention to utilize ordinary gears and associated parts with their attendant advantages in a simplified type of reversing mechanism which Wlll positively start and stop the reciprocable table of a machine tool gradually and Without material shock.

It is a further object of our invention to provide a device of this type with a releasable locking connection between the reciprocable table and the cam operating mechanism whereby the cam will be forced to travel with the table during both the starting and the stopping movements and will be returned. to and released in a central position for normal operation of the machine. v

With these and other objects, as will be apparent from the following disclosure, our invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

Referring particularly to the drawings, in which like numerals indicate like parts, we have there shown one form of our invention in which:

Figure 1 is a front elevation, partly broken away, of a grinding machine base including our invention;

Fig. 2 is a section substantially on the line 2+2 of Fig. 1, with parts of the mechanism removed for the sake of clarity of illustration; v v r Fig. 3 is a side elevation, partly in section, illustrating particularly the cam slide operating lever,

Fig. 4 isa top plan view with the table removed of a portion of the reversing mecha- I nism Fig. 5 shows in a top plan View a detail of the reversing dog mechanism; and

Figs. 6 and 7 are diagrammatic sketches illustrating the driving gear and cam mechanism in two end positions as compared with the central position shown in Fig. 1.

In the practice of our invention we utilizethe principle that if a driven gear and a driving member are moved relative to each other in the same direction as or opposite to that of the periphery of the gear while the driving member isv being 'otherwise'moved normally, the motion of the driven gear, is affected thereby; This relative movement may be between two gears, either in mesh or connected by a chain, which are mounted to move peripherally relative to each other, while the driver movesnormally. 'By controlling this peripheral motion, such as the rolling f two gears on their peripheral pitch line of contact, by means of a cam or other suitable mechanism to produce a gradually accelerated relative movement until the motion of revolution equals that of rotation, the rotary motion of the driven gear is gradually neutralized and may be brought from full speed to rest. Similarly if the outer member is initially rolling along the periphery of the other'gear'and its motion of revolution is gradually retarded while it is rotated at a uniform rate, the inner driven gear is grad- 'ually accelerated from rest to full speed. If

these gears, which may be arranged for external or internal driving contact, are connected one with the machine table and the other through a reversing mechanism with a power shaft, the table may be reciprocated, a cam controlling mechanism being interposed to cause the initial gradual acceleration or retardation at each reversal.

As a specific embodiment of our invention, we have illustrated a machine tool having a reciprocable table 10 of standard construction mounted on V and flat ways 11 f and 12 respectively on a suitable base 13. The driving mechanism therefor, which may be mounted on the base, or in a removable box 141-. as illustrated, comprises a driven gear 15 operatively connected with the table,

' here shown as meshingdirectly with a rack 16 fixed on the under' side of the table 10. In order to rotate gear 15, a driving gear 20 is supported in mesh therewith by means of arms 21 and 22 pivoted on the axis of gear As shown, they may be revolubly mounted on the shaft 23 which supports the driven gear 15. this shaft being suitably mounted in hearings in the box 1 The arms 21 and 22 are secured together at their outer extremities by pins 25 and carry the driving gear 20 suitably mounted therebetween on the shaft 26.

The gear 20, which is revoluble about the gear 15, may be rotated at a substantially uniform rate irrespective of its motion of revolution by means of suitable flexible driving connections. These may comprise universally jointed telescoping members driven by a reversing mechanism. As shown, these parts comprise a socketed member universally connected to the end of shaft 26. A telescoping member 31 siidabl ht within the socket of the part 30 is simili universally connected with the shaft which is mounted in hearings in the box lat. Keyed to this shaft 32 is a driving gear 33, which in turn meshes with a similar gear keyed to the shaft 35 mounted in the lower portion of the box. This shaft 35 is driven alternately in opoosite directions by suitable reversing mec 1anism which may comprise a main driving shaft 36 having the bevel gears 37 and 33 loosely mounted thereon and adapted to be connected to the shaft by means of a shiftable clutch member 39 keyed to the shaft 36 and adapted to engage a clutch portion on the end of one of the bevel gear members 37 or 38, as is well known in this art. These gears 37 and 38 are in mesh with a gear l0 mounted on the end of shaft 35 so that, depending upon which way the clutch is thrown, the driving gear 20 will be rotated in one direction or the other and consequently the table traversed as desired.

In order to obviate the shocks incident to starting and stopping the table, we provide a positively acting cam controlling mechanism which causes the driving gear 20 to assume a secondary motion along the periphery of the gear 15 while rotating continuously and thereby affect the driving action of the latter gear. t will be obvious that if the small driving gear 20 while rotating normally is revolved about gear 15 in a d' 'ectiou opposite to that which it tends to drive the latter first at the full rate of driving and then be gradually retarded in its peripheral motion until it is stationary, the driven gear will be gradually brought from zero to full speed. To this end, we provide a cam'member shown as a slide lf) supported in slideways 46 on the front of the machine. A cam slot 48 of the desired shape and dimensions is provided in this slide and a cam follower therefor, here shown as a pin 50, is rigidly supported on the side of the arm 21 opposite the pitch line of the two gears, passing through a suitable opening in the side of the box 14. By means of this construction the position of the driving gear 20 relative to the gear 15 is detern'iined by the location of the cam follower 50 in the slot 4:8.

While we may move and control the cam slide by various mechanisms, we preferably employ a lever 52 pivoted at 53 on the front of the machine which has a handle 54 at its upper end for manual manipulation of the cam slide. This lever 52 is connected by a link with the slide 45, it being noted that the cam slot might be located directly in the lever, but with its curve slightly changed as will be apparent. The lever 52 is normally held in a vertical position and the cam slot centralized relative to the cam follower, as shown in Fig. 1, by means of a spring pressed plunger 57 mounted within a hollow box 58 projecting from the rearof the handle The lower end of the plunger is made V-sha-ped to lit in a similarly shaped groove 59 in a block 60 fixed on the front of the machine, this block hav ing a curved top surface for the plunger to ride along during movement of the handle. The plunger is held normally in engagement with the block by means of a spring (91 located within box 58 and positioned by. r

the adjustable nut 62 threaded into the upper portion of the opening in the box, the spring hearing at its lower end on the flange 33 onthe plunger and normally pushing downwardly thereon.

The table of the ordinary machine tool is adapted to be traversed through a variable distance. This is accomplished by means of the usual adjustable dogs 65 and 66 which may be clamped in any desired position by means of a T member 67 slidably mounted in the T slot 68 in the edge of the machine table, in accordance with the usual practice. In the simplified construction illustrated, we. have shown the cam slide as moved and controlled by movement of the table. To this end we provide means to connect the lever 52 periodically to the table. This may comprise a lug 70 projecting rearwardly from the handle 52 which is adapted to be engaged by one or the other of the table dogs. In order that the cam operating handle .2 may be held firmly in engagement with the dogs throughout the complete extent of the reversing operation, we provide each dog with a projecting lug 72 separated from the main body of the dog by a groove "73 and the parts are so constructed and arranged that the lug 72 on the dog may pass beneath the lug 70 on the handle and then as the handle is moved forward by the travelling dog, the

will. retain-its an on ite' thaie and move it backward to substantially a vertical posif tion, as shown in Fig. ljwhere'the spring pressed plunger can centralize the handle 2I11d100k forthenormal driving movement of the table.

The direction er rotation of the various parts may be reversed by'a suitable-load and .hre mechanisl'ii a simplifiedconstruction of'which is illustrated-in Fig. 1. As there. show nthe slidable clutch member 39 which is lz'ey ed to theshaft 36 is engaged by a yoke member 75 mounted in a roove 76 of the slidable clutch member. f"'lhis yoke member/T5 has upwardly projecting end portions 7T'andf78 slidably mounted on'the rod 79 which is suitably supported on the machine and surrounded by the springs .80 located between the uprightportions or lugs" 77 and 78; Pivoted locking fingers 82 and 83-aremountedon the rod 7 9,-e'ach hav ing adownwardly projecting shoulder 84 adapted to engagethe outer side of one of the'projecting lugs and to hold the clutch yoke 75 in looking engagement with one.

or the other of the gears 37 or 38.. As

shown, the finger 82 isjlocked behind the" lefthand lug 77; In order to .throw the.

clutch, the member 85 rigidly fixed to the slide is provided with'arms-86 which energy until a finger is moved to release'the' lock, whereupon the cluthisKforcibly and quickly thrown in the desirecl'directionl It will now be evident in view of the above disclosurethat when the cam slide is driving gear 15 and the cam follower v held stationary the niichanism will drive the work tablev at ,a normal and uniform rate, the axis of the driving gear QO bGiII g in ahorizontal plane with the axis of the being located in the central portion of the cam slot as; This'slot 1s madeln 'a sub-.

stantially S-shape, as illustrated, with the; central port on of the, 8 approximately horizontal, so that the normal .upward 'or downward thrust of the pi'n'50 on the cam slot will engage this horizontal portion and preventperipheral movement of the driv ing. gear. In order to'bring thetable' gradually to a stopit is necessary that the driv-v ing gear 20Itrave1 at first slowly and at an increasing rate peripherally. along the driven gear "15 until the clutch hasbeen thrown; Toaccomplish'this purpose the cam slotjis so shaped; as to comply substantially with the law" or falling bodies I as "modified practical considerationsf-inet p with in designingand-operating; the ma 1 chine. As illustrated;i the. outer gliELlVeSf of the 1 slot are substantially. parallel with the periphery of the driven gear 15 and th im terr'nediate portions are" so iformed that the pin 50 will first be moved. at a very slow y central "position and chine. Assuming 'Qthat the table is moving in the direction of the arrow in .Fig". 1,

7 rate; peripherally 'ofj gear "15 adjacent the gradually accelerated as it'tra vels outwardly.

The construction and purpose otthese parts willbe more fully -,underst0od)ifr0ma I .consideration of the operation of themamachine w he efore'operate at a 'c0 tinuous' rate until th dog has. moved overvto the left 'and'struck the; lug on the I ,7 arm 52. The clutch still being connected; I

for driving, to. the leiEt the-dog "66 will move the arm and therefore thefslide 45 following pin 50 to travel along the upper portion of the cam [slot48 and "so 'carry'the A small gear 2.0 with it. At'fir'st-the vertical component of the travel of'this pin" is small vtoward the left. This will cause the-"camand the drivingaction of tlie; 'gea '2O,wi-llmoreits driving action. The efi ect o'f this is to slowdown the traverse ofthe table .be neutralized only to a slight 'eXtei1't',;b11t-Z asthe pin goes up the slotgit is gradually,v assuming a line substantially parallelwith the periphery of the:gear,l5 and the gear v 20 is rolling along its peripherzyf, at'an in creasing rate, thusneutralizing more" and gradually until, when the, pin 50" has" reached theouter stretch of the cam 165f i 48 all driving action Iongear '15 has b n.

neutralized. v "In suitabletimedrelation to the table movement, as is bestldetermined by prac tical adjustment of each machine depending upon the inertia of'the 'rno vable' parts,'the' .I load and]fire mechanism,-"which has been compressing the left-hand portionfotthe" spring 80, l'iftsthe finger 82' and releases the clutch,-causing' it to throw quicklyto the left to engage the opposite gear and thus reversefthe direction of the driving gear 20; This operation may be so timed that the table will bejust stopped as the direction" is reversed; or the 'clutch mayv be thrown before the cam follower has reached the outer portion of the cam path. Reversing the rotary movement of gear20 results in a downward thrust on the cam follower which at first moves at full'speed without starting telv thrust transmitted through the lever and the table lug 72 lessens and thelever ispperniitted to stop in its central driving the table and then gradually transmits more and more thrust onthejtable dog and'the gear 15 to start the table'tow'ards the right.

As the cam follower approaches the horizontal portion of the cam'slot, the horizon- I M i by Letters Patent is:

posit-ion. .The handle 52remains looked to the table during thestarting operation because the lug 7,0 is held in theslot 73 behind the lug T2 on the table. dog and is thus returned to a vertical position Where the plunger 57, which has formerly been forced out of its locking groove, now returns to this groove to holdthe pin 50 centrally located in the cam slot, after which the table is again driven at its normal full speed.

When the clutch is next thrown, the cam follower 50 traverses the lower reaches of the cam slot and the same operations are gone through to stop ant! start the table gradually. The driving gear 20 will thus oscillate between the upper and lower positions shown in 'l igs. (S and '7, depending upon the direction of movement of the table.

Having thus described our invention, what we claim as new and desire to secure 1. A driving and reversing mechanism for machine tool tables compris ng driver and ja driven member in peripheral rolling contact and operatively connected vith the table, means to move the driver uniformly and traverse the table at a nor *al rate for an indefinite period and mec movement pemeznber which and gradually upon the driver a secondary riphe ally. around the driven accelerates its driving action starts the table into motion.

2. A driving and reversing mechanism for reciprocable bodies comprising a rotary gear operatively connected with said body, means including a driver to rotate the gear at a uniform rate, dmechanism ei'lective 'to revolve said driver and gear relative to each other peripherally at an increasing rate to neutralize the driving action and bring the table gradually to a stop.

3. A driving and reversing mechanism for machine tool tables comprising a rotary driven member operatively connected with said table. a driving member therefor, means to move said driving member at a normal rate and cam cont-rolled mechanism *efi'ective to impress an accelerated secondathe driver at a normal rate and cause the table 'to be stopped and started gradually. 5. A driving and reversing mechanism ism etlecthe at the period of reversal to impress for the reciprocable table of a machine tool 7 comprising a rotary driven member operatively connected with the table, a rotary driver revoluble about theaxis or said driv en member, and positively actuated mecha:

nism to rotate said driver and simultaneously revolve it at adecreasing rate to start the table gradually into motion.

6. In a machine ,tool having a reciprocable body, a drivengear operatively connected with sa1d tab1e,.a rotatable driving gear revolu'ble peripherally in mesh with said-driven gear, means to rotate said drivdecreasing rate to start said table gradually, into motion and thereaiter drive it at a uniform ratebefore reversal.

7. A driving and reversing mechanism for machine tool tables comprising a driven gear operatively connected wlth the table,

a driving gear meshing therewith, means to support said driving gear for apartial revolution about the axis of the driven gear, ir ans to rotate said driving gear in oppoirectious at a uniformrate, and cam con olling mechanism effective to limit the peripheral motion of the driving gear about the driven gear to start and stop the table dually and thereafter to drive it at a uniform rate between reversals.

in amachine tool having a reciprocable table, a drivengear operatively connected mg gear in opposite directions, and means 1 to revolve the motatrng driving gear at a with said table, a driving gear meshing with and mounted toswing about the axis d driven gear, means to rotate said (ill gear in opposite directions, and means controlled by movement of the table to swing said driving gear at an increasing and then decreasing rate aboutsaid driven gear to stop and start the table gradually 1 and thereafter to drive said table at a uniform rate. I

9. in a. machine tool having a reciprocable table, a. driven gear operatively connected therewith, a driving gear meshing with and mounted vto swing about the axis of said driven gear, means to rotate said driving gear in opposite directionsirrespective of its movement of revolution, and means comprising a movable cam device and a releasable control member operated by the table effective to cause the driving gear to move at an increasing and then a decreasing rate in opposite directions alongthe periphery of the driven gear toneutralize the effect of then'ormal driving action and stop and start the table gradually.

10. In a machine tool having a recipio' cable table, a driven gear opera-Lively con nected therewith, a driving gear supported fora partial revolution about the axis of the driven gear and in mesh therewith, a mov able cam member, a cam follower'revoluble with said driving gear, and meansoperated by said table effective to move said cam member and the follower when the direction of table movement is to be reversed, saidcam member and follower being shaped and arranged to cause the driving gear to move peripherally of the driven gear at a decreasing rate to start the table gradually into motion and thereafter drive the table at a uniform rate.

11. In a machine tool having a reciprocable table, a driven gear operatively connected with said table, a driving gear supported for a partial revolution about the axis of said driven gear and'in mesh there-- with, reversing mechanism including a clutch to rotate the driving gear in opposite 12. A driving and reversing mechanismfor a machine tool table comprising driving and driven members, means controlled by the table to move one member relative to the other to partially neutralize the driving action and causethe table to start gradually into motion, and a locking device operatively connecting said means and the reciprocable table during the startingaction-and releasing said connection thereafter for driving the table at its normal rate.

13. In a machine tool having'a reciprocable table, a driven member operatively connected therewith, a drivingmember there for, and means controlled by movement of the table to impress upon the. normal action between the driving and driven members a;v

relative secondary motion which will cause the table to start gradually, including a movable cam controlling device and a'lock-I ing member operatively connecting said device with the table during the starting act-ion indefinite traversing movement.

p 14. In afimachine tool havmg a reciprocable table, a driven gear operatively conand releasing it therefrom. for the normal nected therewith, a. rotary member to drive 1 V i said gear, cam controllin mechanism effective to impress a secon arymotion upon said rotary member to neutralize its driving action and causes the table to start and stop gradually, and a locking device connecting said mechanism with the table for controlling the starting and stopping action which automatically releases such c0nnection for the normal indefinite traverse of the table between reversals;

Signed at Worcester, Massachusetts, this 27th day of June, 1921. Y

. IGREGORY BROWN.

. ALBERT TURNER. 

